This invention relates to pulsator valves and has been devised particularly though not solely as a pulsator valve for a milking machine system.
In most conventional milking machine systems a pulsator valve is provided to connect alternately a vacuum supply or atmospheric pressure to the cavity between the teat cut body and a flexible teat cup liner. When `vacuum` is connected to this cavity is tends to balance or counteract the effect of vacuum connected to the inside of the liner and the liner will assume its natural normally cylindrical shape. When atmospheric (or other) pressure is connected to this cavity the liner is collapsed squeezing the teat.
Common types of pulsator valves at present in use may incorporate a plate, reed or spool as the valving means which may be actuated by a variety of mechanisms. In most existing pulsator designs a situation may arise where, when the valving means is being driven from one position to another (i.e. from connecting vacuum or atmospheric pressure to the outlet port) both the vacuum and atmospheric ports are connected together and/or to the outlet port. This may give rise to unstable operation and/or a variable or undesired output `pulse` profile.
Some types of conventional pulsator valves will normally unless made to unreasonably fine engineering tolerances, have all ports connectd together at some time in its operating cycle.
It is therefore an object of the present invention to provide a pulsator valve which will at least provide the public with a useful choice.